Each roulette table has its own limits. These limits can be low or high but all casinos set them, and there are good reasons for that. Roulette table limits can be much higher than slot max bets. That’s because one bet can’t win players more than x35, while slot machines can pay over x10'000 for a single bet. That’s why casinos set roulette bet limits that are usually higher. You can find some casinos offering 50'000 and even 100'000 Euro max limit. But only big and rich casino operators can afford that.
In the long run casinos always win. That’s because of the house edge. It looks like they shouldn’t be afraid of accepting crazy big bets and should be happy when someone places them. But this isn’t that simple. Players always have a chance of winning when they play at legitimate casinos. Operators don’t know game outcomes in advance and therefore take risk every time someone places a bet. If one or several big players have a huge win, casinos can have difficulties paying the money.